The stand-off scored a hat-trick against Hull FC but followed up with a poor display in last week’s loss at Wigan Warriors.
Powell had wondered afterwards if he had received too much praise for his Hull performance.
But yesterday, ahead of their elimination tie at Warrington Wolves on Thursday, he said: “Players get put under pressure and Truey had an outstanding game the week before.
“It is about consistency now. For him it’s about developing a consistent level when teams recognise how good you are and come after you. Our kicking game was a little bit off, but I just thought we were off as a team in terms of our attacking execution.
“I am not going to put it all on a young bloke like him who has got such a big job to do. The team has got to be better to allow him to do his job a bit better. That goes down to both half-backs getting our execution right.”
Challenge Cup holders Warrington finished just above Castleford in fourth and have been badly out of sorts before and after Wembley.
Powell said: “I think Warrington have been great all year, until around the Challenge Cup.
“But they’ve been talking up it being a one-off game and how good they’ve been in one-off games this year. It is hard to argue against that, but I think for us it’s just get ourselves right and enjoy the experience and the challenge of what’s in front of us.”
Castleford will be without second-row Jesse Sene-Lefao who has received a two-game ban for his red card at Wigan. But Wolves have lost scrum-half Matty Smith to a one-game ban and Hull KR hooker Matt Parcell is out for three games on a dangerous contact charge.